timer-count

Arguments:
timer

This function returns a non-negative integer indicating the number of
times that a timer's interval has elapsed since it was most recently
started. This value is supplied for general information, and is not
used internally by Common Graphics. An application could modify this
value if desired, though there is probably no reason to do so.

When a timer is started, this property is set to zero. Each time a
timer's interval has elapsed, the default
timer method increments
the timer's timer-count by one and then calls its on-timer function. If a timer count
reaches 500 million, it is reset to zero to prevent the consing of
bignums.